2I 4 CRUSTACEA MALACOSTRACA. Ill 



C. Hanseni as figured by Sars or Giard & Bonnier; furthermore trie antennulse on Sars' figure agree 

 fully with their shape on the French figure, and it may be added that my examination of the anten- 

 nulse of a male of C. Hanseni showed the figures mentioned to be correct. In C. Meinerti the first 

 joint is extremely large, almost twice as broad as long, while in C. Hanseni it is considerably less 

 produced backwards, scarcely half as broad again as long; furthermore the front margin of the joint 

 is longer in C. Hanseni than in C. Meinerti, finally the posterior margin has n teeth in both species, 

 but in C. Meinerti the teeth are more closely set, and the major part longer than in C. Hanseni. Se- 

 cond joint of the antennulse shows some difference in the armature of the distal margin in the two 

 species, but in the shape of the three posterior pairs of legs (figs, i a— t c) no appreciable specific 

 difference could be discovered. — The males of C. Meinerti are about 077 mm. long. 



Occurrence. The infested specimens of Synidothea nodulosa Kr. are from West Greenland, 

 partly from Godhavn, L,at. 6o. c i4' N., partly without special locality, but probably from a more southern 

 locality. The infested specimen of Pleuroprion Murdochi Ben. is — see p. 196 — either from Iceland 

 or the Fseroes. 



Distribution. Jugor Schar, entrance to the Kara Sea, a specimen of Synidothea nodulosa 

 Kr. with the parasite (Giard & Bonnier). 



Arcturocheres n. gen. 



Immature Female. The body (PI. XVI, fig. 2a) shaped as an oblong sac, with the mouth 

 much reduced but distinctly seen (fig. 2 b); most of the ventral side divided by six feeble, transverse 

 furrows, and two pairs of minute sublateral legs (/) placed respectively a little before and a little be- 

 hind the middle; each leg is minute, rounded, somewhat plate-shaped, freely protruding and well 

 chitinized. 



Male. Differs from Clypeoniscns especially in the antennulse and in the two posterior pairs of 

 thoracic legs. First joint of the antennulse (fig. 2 e) has only four teeth on the posterior part of the 

 inner margin and on the posterior end. Sixth joint, the hand, of each of the two posterior pairs of 

 legs with two spines at the lower margin; on seventh pair (fig. 2 k) seventh joint constitutes together 

 with the claw a normal, slender and long "claw", but on sixth pair seventh joint (figs. 2 h and 2 i) is 

 quite aberrant, being rather short, unusually deep, and increasing in depth from the base to the end, 

 which is cut off obliquely and has the normal, slender claw inserted at the upper angle on its termi- 

 nal margin. 



Remarks. It was found necessary to establish this genus on a new species parasitic on spe- 

 cimens of the genera Astacilla and Pie?tro/>rion, as both the male and the female differ materially from 

 the other genera hitherto known. 



154. Arcturocheres pulchripes n. sp. 

 (PI. XVI, figs. 2 a— 2 1). 



Immature Female. The single specimen is somewhat compressed, but that may be acci- 

 dental. As shown in fig. 2 a, the contents form a body more or less removed from the pellucid thin 



